Trolling attachment for outboard motors



Sept. 5, 1961 A. DOWNIE ET AL TROLLING ATTACHMENT FOR OUTBOARD MOTORS Filed April 6, 1960 INVENTORS flaw/w? flan M5 J41 ra/v fl/ fizz/501 ATTORNEY United States Patent V V 2,998,795 TROLLING ATTACHMENT FOR OUTBOARD MOTORS Arthur Downie and Dalton W. Haubold, Denver, Colo.,

assignors to Spinn-Con-Troll, Inc., Denver, Colo., a

corporation of Colorado Filed Apr. 6, 1960, Ser. No. 20,436 3 Claims. (Cl.i114-145) -of outboard motors without effecting the operation or structureof the outboard device in any way.

A further object is to provide a trolling plate and a trolling plate mounting for outboard motors which will enable the plate to be minutely and accurately adjusted to obtain and maintain any desired trolling action independently of the motor speed.

Other objects and advantages reside in the detail construction of the invention, which is designed for simplicity, economy, and efiiciency. These will become more apparent from the following description.

In the following detailed description of the invention, reference is had to the accompanying drawing which forms a part hereof. Like numerals refer to like parts in all views of the drawing and throughout the description.

In the drawing:

FIG. 1 is a side view of a conventional outboard motor showing the improved trolling attachment applied thereto;

FIG. 2. is an enlarged, fragmentary perspective view of the outboard motor with the trolling attachment applied thereto;

FIG. 3 is a still further enlarged detail perspective view of a clamping member used in attaching the attachment to the propeller standard of a conventionalmotor;

FIG. 4 is a cross sectional view of the clamping member, taken on the line 4--4, FIG. 3;

FIG. 5 is a reduced scale detail perspective view of the bottom of a motor attachment plate employed for mounting the attachment on the outboard motor;

FIGS. 6 and 7 are similar perspective views of adaptors for use with the plate of FIG. 5 as will be later described;

FIG. 8 is a similar detail perspective view of the bottom of a control bracket used in the attachment;

FIG. 9 is a detail rear face view of a trolling plate employed in the invention; and

FIG. 10 is a detail side view, partially in section illustrating an extensible adjusting shaft device employed for adjusting the angle of the trolling plate of FIG. 9.

In the drawing, elements of a conventional outboard motor are designated by numerals as follows: motor housing 10, motor housing flange 11, motor housing flange bolts 12, propeller shaft housing 13, anti-cavitation fins 14 on propeller shaft housing, and propeller 15.

The improved trolling plate attachment is designed for application to the motor housing flange 11 and the anti-cavitation fins 14 of the propeller shaft housing 13 through the medium of a pair of propeller shaft housing clamps 16 and 17, and a mounting plate 18.

The propeller shaft housing clamps are similar but of opposite hand, that is, the clamp 16 is a right hand clamp designed to fit against the right side of the propeller shaft clamps 16 and 17 are drawn together and tightly clamped against the sides of the propeller shaft housing 13 and over the fins 14 by means of rear clamp bolts 20, positioned to the rear of the propeller shaft housing 14, and a forward clamp bolt 21 positioned forwardly of the housing 14. The rear clamp bolts 20 pass through suitable bolt holes 22 extending through upper and lower bolt pads 23 and 24, respectively, formed on the rear extremity of the inner edge of each clamp. The forward clamp bolt 21 extends through a forward bolthole 25' extending through the forward extremity of each clamp.

The mounting plate 18 is provided with a notch 27 in its forward edge to enable it to receive and fit about the motor housing 10 for attachment to the motor housing flange .11.. The method of attachment depends upon the particular make and type of outboard motor. For instance, on certain motors, the mounting plate can be rested on the motor housing flange and secured in place by passing the conventional flange bolts 12 through elongated bolt holes 28 in the mounting plate. On other types of motors, thenotch 27 can be placed around the flange 11 and secured to the flange bolts 12 by means of adaptors such as shown at 29 in FIG. 6 or 30 in FIG. 7. The adaptors are provided with suitable bolt holes 31 for receiving the bolts 12 and other suitable attachment bolts 32 extending through convenient bolt slots 33 in the mounting plate. Thus, a substantially universal mounting is provided for any type of motor.

The clamps 16 and 17 conform in shape to the conventional shape of the fins 14, that is, they are transversally wider at their rear extremities than at their forward extremities and each is provided with a rearwardly extending pivot car 26 at the outer corner of its widened rear extremity.

A trolling plate 34 is suspended from the rear extremity of the housing clamps 16 and 17. The trolling plate 34 is provided with forwardly extending pivot cars 35 adjacent its upper edge which fit against the pivot ears 26 and are pivotally secured thereto by means of pivot bolts 36. The trolling plate 34 is generally flat with forwardly turned vertical side edges 37.

A bracket plate 38, a bottom view of which is shown in FIG. 8, is bolted beneath the mounting plate 18- by means of suitable mounting bolts 39 extending through elongated bolt holes 4%) in the bracket plate 38. The bracket plate extends rearwardly from one side of the mounting plate and supports a ball bearing plate 41 through which an upright tubular adjusting shaft 42% ex tends. A spherical enlargement or bearing ball 46 is formed on the tubular adjusting shaft which is clamped in place by the bearing plate 41 to swingably support the adjusting shaft 42.

The adjusting shaft 42 terminates at its top in a hand crank 44 and at its bottom in an enlarged, internally-threaded nut portion 45. A jack screw 46 is threaded through the nut portion 45 and into the hollow interior of the tubular adjusting shaft 42. The jack screw 46 can be locked at any desired degree of extension from the tubular adjusting shaft be means of a jam nut 51. The lower extremity of the jack screw 46 is threaded through a head 47 on a pivot pin 48 which is rotatably mounted in a pivot car 49 on the trolling plate 34.

Thus, it can be seen that when the jack screw is locked against rotation in the tubular adjusting shaft by means of the jam nut 51, clockwise rotation of the hand crank 44 causes the internally threaded head 47 to move uptrolling plate.

wardly so as to swing the trolling plate rearwardly and upwardly from the vertical position of FIG. 2 to any desired intermediate position, such as shown in FIG. 1, or to a substantially horizontal, rearwardly extending position. Counter clockwise rotation will, of course, reverse the direction of movement so as to swing the trolling plate downwardly. Thus, the propelling reaction of the propeller stream upon the boat can be minutely and accurately controlled to obtain any desided propelling effect from a full stop, with the trolling plate in the vertical position of FIG. 2, to full speed ahead with the trolling plate in the horizontal position.

The maximum arc of movement of the trolling plate is preset by means of two spaced limit stops, such as set collars 50, on the jack screw between which the head 47 travels. The collars are so spaced that when the head 47 contacts the lower collar the trolling plate will be in the vertical or full stop position and when the head contacts the upper collar 50, the trolling plate will be in the horizontal or full speed ahead position. Thus, accidental overriding is prevented without any attention on the part of the operator. It will be noted a complete rotation of the control crank moves the trolling plate only the pitch distance of the threads on the jack screw. Therefore, a very accurate and minute adjustment of the boat speed can be attained.

Attention is called to the universality of attachment of the improved trolling attachment. The mounting plate with its plurality of bolt holes 28 and 33, and with its .various adaptors 29 and 30, can be quickly fitted to any conventional motor housing. The adjustability of the clamp bolts 20 and 21 makes the propeller shaft housing clamps 16 and 17 adaptable to various propeller shaft housings. The adjustability of the bracket plate 38 with reference to the mounting plate 18, due to the elongated bolt holes 40 provides for various forward and back positions of the mounting plate on various motors. The adjustment of the jack screw 46 in the tubular shaft 42 provides for easy and rapid vertical adjustment for motors of varying vertical spacing between the motorand the anti-cavitation fins 14.

The anti-cavitation fins 14 are a very important and essential element for all efficient outboard motors. Therefore, any interference with their action is, of course, not desirable. It will be noted that with this attachment, the planing effect of the fins is not only not disturbed but is enhanced by clamps 16 and 17 which follow the contour of, and lie in the plane of, the conventional fins so as to increase the anti-cavitation qualities of the standard fins.

It will be noted from FIGS. 2 and 9 that the forwardly turned edges 37 on the trolling plate 34 have a greater width at their bottoms than at their top. In other words, a greater edge area is turned forwardly as the bottom of the plate is approached so that the plane area of the plate narrows as the bottom is approached to give a shovel-like contour. The latter contour acts to confine and direct the propeller stream as it discharges rearwardly and downwardly from the trolling plate to provide effective steerage way at relatively low speeds without side wash effect.

The shovel-like shape of the trolling plate is necessary to direct the propeller stream downward and away from the transom of the boat at all positions of the If the vertical edges of the trolling plate '4 were of uniform width throughout their length they would act, when approaching the position of FIG. 2, to form a uniform trough which would cause a portion of the propeller stream to boil upwardly over the transom of the boat.

While a specific form of the improvement has been described and illustrated herein, it is to be understood that the same may be varied within the scope of the appended claims, without departing from the spirit of the invention.

Having thus described the invention what is claimed and desired secured by Letters Patent is:

1. Means for pivotally suspending a trolling plate rearwardly of a propeller of an outboard motor of the type having a propeller shaft housing with relatively thin anti-cavitation fins extending oppositely outward from the sides of said shaft housing above said propeller comprising: two relatively flat, hollow clamping members of sufiicient length to extend forwardly and rearwardly of said anti-cavitation-fins and being provided with openings in their inner edges to receive said fins into their hollow interiors; means clamping said clamping members toward each other forwardly and rearwardly of saidfins so that said members will completely enclose both of the latter; and a hinge device mounted on the rear extremity of each clamping member, said trolling plate being swingably suspended from said hinge devices rearwardly of said propeller.

2. Means for pivotally suspending a trolling plate as described in claim 1 in which said clamping members are contoured to present a cross section to the water similar to the cross section of the anti-cavitation fins so that the action of thelatter will be continued by said clamping members.

3. A boat speed control attachment for an outboard motor of the type having a motor housing flange and a propeller shaft housing provided with anti-cavitation fins comprising: a pair of propeller shaft housing clamps; means for clamping the clamps of said pair against opposite sides of said propeller shaft housing so as to extend rearwardly therefrom; a trolling plate pivotally suspended from the rear extremities of said clamps; a mounting plate; means for securing saidmounting plate upon said motor housing flange above said clamps; a shaft bracket secured to and extending rearwardly from said mounting plate; a threaded jack screw and nut combination extending between said shaft bracket and said trolling plate; means for imparting relative rotation between said screw and nut to vary the length of the combination, said jack screw and nut combination 'comprising a tubular shaft supported and depending from said shaft bracket; a jack shaft threaded into and extending downwardly from said tubular shaft; means for locking said jack screw at any desired extension from said tubular shaft; an internally threaded head member threaded on said jack screw; and means for hingedly mounting said head member on said trolling plate.

References Cited in the file of this patent UNITED STATES PATENTS 2,200,836 Didriksen May 14, 1940 2,787,974 Johnson Apr. 9, 1957 FOREIGN PATENTS 14,363 Great Britain Nov. 24, 1885 

